Scaffold jack



FIG. 1 is a perspective view of a scaffold jack showing my new design;

FIG. 2 is an end elevation view thereof, the opposite end being substantially a mirror image of the end shown herein;

FIG. 3 is a front elevation view thereof; and

FIG. 4 is a top plan view thereof.

The rear and bottom of the scaffold jack are substantially flat and unornamented. 

The ornamental design for a scaffold jack, as shown and described. 